Low-mow maintenance: Highway habitat lessons

The most recent edition of Wild Ones Journal featured a cover story by Dianne Kahal-Berman, an Ohio DOT engineer, about highway pollinator habitat. Dianne wrote about how the FAST Act that was signed into law last December will boost pollinators through our highway programs. In addition to long-term highway infrastructure fixes, Section 1415 of the FAST Act includes provisions to restore pollinator habitat along roadsides. It’s a clear signal to all 50 U.S. states that managing highway rights of way for pollinators is a national priority.

The bill’s language encourages “integrated vegetation management practices on roadsides and other transportation rights-of-way, including reduced mowing” and “development of habitat and forage for Monarch butterflies, other native pollinators, and honey bees through plantings of native forbs and grasses.” The best part is that states may use federal highway funds appropriated for weed control and to establish native plants to also provide pollinator habitat as well, so the effort is financially hardwired.

The effects of FAST Act changes authorizing how state DOTs spend money to plant and maintain federal highways will be implemented over time. Meanwhile, a couple of states have been very active in promoting habitat.

Florida, for example, has questioned the need to mow from roadside to fence line. Instead they’re looking at ways to reestablish wildflower and pollinator habitat while maintaining highway sightlines and safety. In rural Madison County, Florida DOT tested reduced mowing regimes for four years from 2009-2013 along a 1-mile stretch of I-10 east of Tallahassee. Only 10- to 15-ft. safety strips adjacent to the inside and outside lanes of pavement were mown regularly; the entire right of way zone was mowed only one time in the fall.

In the low-mow test zones they noted high plant species diversity, many of them showy wildflowers that the state has begun to promote for tourism. Mowing costs were reduced, in addition to less expense on fertilizers. Most herbicide applications were eliminated except for control of exotic invasive plants. Results from the study projected that if reduced mowing were adopted statewide, and roadside vegetation were regarded as an asset, the state would see $2.2 million alone in aesthetic ecosystems services. The value of pollination services from adding wildflower habitat statewide through reduced mowing is conservatively estimated at $34 million. The report concluded there were “no adverse impacts regarding erosion, safety, aesthetics or turf quality.”

Conoclinium coelestinum was one of the attractive native wildflowers on Florida’s I-10 test low-mow corridor.

Further north, Ohio DOT says half of their districts are already involved in planting habitat. Ohio DOT, led by Dianne in District 9, is pushing the state to do their part to restore or enhance the Obama Administration’s 7 million acre national pollinator habitat goal. Ohio’s share would be 145,834 acres. To push into more significant increases, Ohio is looking at changing roadside maintenance to increase habitat faster than just focusing on highway plantings. To that end, Ohio DOT is testing low mow regimes in a study that will wind up this fall. Ohio DOT’s low-mow test is studying reducing mowing areas beyond the ditch line to once per year instead of the current four times to allow habitat to form while simultaneously preventing establishment of subshrubs or trees.

The U.S. Department of Transportation isn’t the only federal agency focusing on roadside habitat and putting money on the table to do so. Perhaps the biggest, boldest highway pollinator example will be the six-state I-35 Monarch Corridor that intends to provide 1,500 continuous miles of Monarch habitat from the Mexican to Canadian border through Texas, Oklahoma, Kansas, Missouri, Iowa and Minnesota. To jumpstart the initiative, the National Fish and Wildlife Foundation awarded $3.3 million in 2015 to a range of groups, including the North American Butterfly Association, Pheasants Forever, Audubon, U.S. Forest Service, U.S. Fish & Wildlife, Nature Conservancy, Xerces Society, universities, state agencies and individual cities like St. Louis. The money will be used to develop wildlife habitat in a 200-mile band along the I-35 corridor.

Look for continued strong demand for native perennials and annuals that benefit pollinators. Based on new federal direction, the public will be seeing more and more wildflowers and butterfly weed through their windshields that can’t help but increase consumer demand. Who knows – maybe homeowners will become so accustomed to seeing taller habitat vegetation that they’ll chose it for portions of their own landscape, too.